| 摘要: | 都市熱島是因為都市地區建築物密集，使用大量電力或石化燃料之人工熱源，以及大量採用蓄熱量高與吸熱表面積大之材料，使得日間都市地區溫度升高後，至晚上以至午夜降溫速度緩慢，相對的，都市郊區或外圍地區因建築物與鋪面較少，綠覆比例較高，於晚上以至午夜降溫速度較快，所造成晚上以至午夜都市地區溫度高、郊區或外圍溫度低之現象。換言之，由都市中心往外到郊區或外圍於中午、晚上、午夜各時段間之降溫幅度會於差異，一般而言，中心區於3個時段之降溫幅度將較小，而郊區或外圍地區於3個時段之降溫幅度將較大。此種降溫幅度之差異可能與各地區之土地覆蓋以及微氣候（包括：濕度、風速、日照等）有關，本研究實證臺北市各地於中午、晚上、午夜時段熱島降溫幅度與土地覆蓋及微氣候間之關係。本研究將台北市23,332個道路街廓交集點，隨機抽取1000點作為樣本點，其次考量道路之可及性劃成25個調查分區並事先規劃好調查路線，在2011年8月20日中午、晚上及午夜三個時段，以同步性機車移動方式，在各樣本點量測溫度、濕度、風速等，以及利用2007年國土利用調查資料量測土地覆蓋與土地利用。本實證結果顯示：（1）發現有4個核心之熱島現象，分別座落在大同區、中山區、士林區、北投區。（2）都市熱島降溫幅度與自然覆蓋比例有顯著性之相關，自然覆蓋比例高者熱島降溫幅度較大。（3）迴歸模式估計顯示減緩熱島降溫之重要因子主要為自然覆蓋比與濕度比，以雙對數函數估計結果為準, 自然覆蓋比每增加1％，熱島降溫0.011%﹔晚上或午夜濕度與中午濕度比（其值大於1，因為中午濕度低於晚上或午夜濕度）每增加1％，熱島降溫2.795%。都市郊區或外圍自然覆蓋率較高，且濕度從日間至夜間濕度增加較快，所以熱島降溫幅度大於都市中心地區，此發現可做為以調整土地覆蓋或土地使用規劃作為熱島降溫策略之參考。
The urban heat island is resulting from the urban residents in the densely central area consume a huge amount of electricity and fossil fuels which generate a large amount of artificial heat, and the paved surface in the dense urban areas absorbs and stores heat. Thus the temperature in the city center, suburbs or peripheral at noon, evening, and midnight is different. In general, the temperature in the central area is dropping slowly from noon to night or midnight, while the temperature in suburbs or outlying area will be dropping much faster from noon to night or midnight. Namely, the cooling rates in the city center, suburbs or peripheral at noon, evening, and midnight is different. Such cooling rate differences may be related to regional land cover and microclimate (including: humidity, wind speed, sunshine, etc.).The purpose of this study is to empirically test the relationship between the heat island cooling rate and the land cover, and microclimate factors in Taipei City.In this study, a random sample of 1,000 points from 23,332 road intersections are selected. The sample points are then divided into 25 survey groups and surveyed on August 20, 2011 at three periods of time(noon,night, and midnight), measuring temperature, humidity, wind speed, etc., and using national land survey data to measure land cover and land use. The empirical results include: (1) There are four cores of heat island located in Datong District, in the mountains, in Shihlin, and in Beitou District. (2) The natural coverage and the relative humidity are factors which have significance effects on cooling the temperature in Taipei City. (3) Based on the double-log model, 1%,increase in natural coverage will result in 0.011% of the air temperature ; 1% increase in humidity ratio will cooling down 2.795%. of the temperature. Suburban or peripheral natural coverage is high, and humidity from day to night humidity increases rapidly, so the heat island cooling rate greater than the urban center. This finding can be used as a reference to the adjustment of land cover or land-use planning as a heat island cooling strategy.
Keywords: heat island, heat island cooling differences, land cover,
microclimate |
